This invention relates to an artificial tooth for substituting a natural tooth lost by dental diseases
Up to the present, metals such as titanium and ceramics such as alumina or hydroxyapatite, have been utilized as the materials for artificial teeth. However, the artificial teeth made of metals present problems in biocompatibility since they tend to be attacked and dissolved in the living tissues, while being higher in hardness and modulus of elasticity than those of the bone tissue. The artificial teeth made of ceramics also present problems with respect to brittleness, hardness and machinability.
An artificial tooth comprising a metal core and a ceramic coating applied to the core has also been produced and offered to the market. However, these artificial teeth have not been used extensively because of the rather weak connection between the metal and the ceramics.
For overcoming the above inconveniences, there has recently been evolved an artificial tooth including an outer contacting portion which is formed of a composite material exhibiting biocompatibility and which is disposed in contact with the alveolar bone, a metal member disposed at the inner side of the contacting member and having an opening, a metal post introduced into the opening and an elastic buffer member adapted for filling in a gap between the metal post and the metal member (Japanese Unexamined Patent Publication No. 152449/1987). This artificial tooth has a drawback that it does not necessarily produce a sufficient buffer action such that the extent of possible movement of the metal post under the tooth pressure applied to the post is less than that in the natural tooth, while the artificial tooth cannot be produced in a configuration which will exhibit sufficient strength and sufficient extent of movement of the metal post.